The warning comes as ISIS face being finally routed in Syria as fighters supported by British and U.S. special forces close in for the kill.

This frame grab from video posted online Friday, Jan. 18, 2019, by supporters of the Islamic State group, purports to show a gun-mounted Islamic State group vehicle firing at members of the U.S.-backed Syrian Democratic Forces, in the eastern Syrian province of Deir el-Zour, Syria.
(Militant Photo via AP)

On Monday, Kurdish-led coalition forces battled to clear the village of Baghouz, where the remaining jihadis are holed up in fortified positions.